Gaseous electric discharge device



March 13, 1934. H. LEMS 1 6 GASEOUS ELECTRIC DISCHARGE DEVICE Filed Aug.17, 1932 INVENTOR 95 m BY buzz.

ATTORNI-IZY Patented Mar. 13, I 1934 1.951.150 GASEOUS ELECTRIC mscmaonnavrca I Hendrik Lems, Eindhoven, Netherlands, assignmto GeneralElectric Company, a corporation of New York Application August 17, 1932,Serial No. 629,204

In Germany August 19, 1931 '4 Claims. (01. 176-124) The presentinvention relates to gaseous electric discharge devices generally andmore particularly the invention relates to methods and means forstarting and operatingsuch' devices equipped with auxiliary electrodes.

It is well known in the art that the starting potential of a gaseouselectric discharge device is higher than the operating potential thereofand that the absolute starting potential is in most cases extremely highparticularly in those devices having a long positive column. The objectof the present invention is to decrease the starting potential ofgaseous electric discharge devices. Another object of the invention isto start and operate on a determined potential gaseous electricdischarge devices having a longer discharge path than has hitherto beenfound practicable on such potential. Still further objects andadvantages attaching to the device and to its use and operation will beapparent to those skilled in the art from the following particulardescriptionand from the appended claims.

The invention attains its objects by providing one or more pairs ofauxiliary electrodes in the container of the electric discharge device.Said auxiliary electrodes are in close proximity to the main dischargesupporting electrodes, extend along the longitudinal axis of thecontainer of the device, are connected through an impedance to anauxiliary current source of a higher potential than the current sourceto which the main discharge supporting electrodes are connected and eachis of the opposite polarity with respect to the main electrode to whichit is adjacent.

In the drawing accompanying and forming part of this specification twoembodiments of the invention are shown, in which Fig. l is a schematicview of one embodiment of the new and novel electric discharge deviceand a circuit therefor, and

Fig. 2 is a similar view of another embodiment of the new and novelgaseous electric discharge device.

Like numbers denote like parts in both the figures.

Referring to Fig. 1 the gaseous electric discharge device illustratedhas a container 1.

I Said container 1 has electrode chambers 2 and 3 and thermionicelectrodes 4 and 5 are sealed into stems 6 and '7 of said chambers 2 and3 respectively. Said electrodes 4 and 5 consist of a coiled wire, suchas tungsten wire. coated with an electron emissive material as an oxideof an alkali earth, such as barium oxide. Two auxiliary electrodes 8 and9 are sealed into said stems 6 and '7 respectively and extend along theaxis of said container 1. Said electrodes 8 and 9 are physicallyconnected by a body of insulation material such as a glass bead 10. Saidcontainer 1 is filled with an electric discharge conducting gaseousatmosphere such as a rare gas, a common gas or a metal vapor or amixture of these such as a mixture of argon and mercury.

The auxiliary electrodes are connected through resistances 11 and 12respectively to the secondary coil 13 of the transformer 14. Themid-point of the primary 15 of said transformer 14 is connected to themid-point of said secondary 13, as shown. The transformer 14 isconnected to the terminals of an alternating current source 16 of 110 or220 volts. The thermionic electrodes 4 and 5, which are the maindischarge supporting electrodes, are connected to the secondaries 1'?and 18 respectively of the step-down transformer 17, 18,- 24. Theprimary coil 24 of said stepdown transformer is connected to theterminals of said current source 16 to furnish the heating current forsaid electrodes 4 and 5. The operating potential is supplied to theelectric discharge device by leads l9 and 20 connected to the terminalsof said current source 16 and to the mid-points of said secondary coils1'7 and 18 respectively. An impedance 21 is connected into one of saidleads 19 and 20' in series with the discharge path.

The transformer 14 is so designed that the potential from the secondarycoil 13 is higher than that of the current source 16. The connectionsare such that when main electrode 4, for example, is negative theauxiliary electrode-8 is positive. The higher potential supplied by thesecondary coil 13 causes the potential between the auxiliary electrodesBand 9 to increase more rapidly than the potential between said mainelectrodes 4 and 5. Thus a glow discharge takes. place between theadjacent ends of said auxiliary electrodes 8 and 9 and an arc dischargetakes place between said auxiliary electrodes 8 and 9 and said mainelectrodes 4 and 5 respectively which quickly and heavily ionizes thegaseous filling in the discharge path between said main electrodes 4 and5 to facilitate the starting of the positive column discharge in saiddevice.

The current flow in said secondary coil 13 and the auxiliary electrodes8 and 9 is comparatively small due to resistances 11 and 12 connectedinto the circuit thereof. The value of said resistances 11 and 12 isfrom 1,000 to 10,000 ohms, as desired. and said resistances are replacedby a. choke-coil or a condenser where desired. The 110 its "transformer14 is accordingly of very small size.

An electric discharge device having a container 1 m. in" length, 40 indiameter, filled with neon at 1.8 mm. pressure and having the structureabove described and connected tothe above described circuit is startedinto operation by' a potential of 180 to 190 volts. The potential of thesecondary coil 13 is then 360 volts.

The gaseous electric discharge device illustrated in Fig. 2 is similarto that shown in Fig. l with the exception that in this embodiment theelectrodes Sand 9 are covered at those parts thereof adjaeent the maindischarge supporting electrodes 4 and 5 with'a body ofinsulation material such as a porcelain tube to preveritthe spattering of materialfrom said electrodes 8 and 9. The'parts of said electrodes 8 and 9adjacent eachjother are surrounded be a metal grid or net 23 which issupported by the inner wall of said container 1. Said net 23 interceptsthe spattered particles from the adjacent and parts of said electrodes.8 and 9 to prevent said particles from depositing on the wall of saidcontainer 1 so that; the transmission of the light rays through saidcontainer 1 is not effected by said spa'tterecl particles. 7

The starting and operating characteristics of the device illustrated inFig. 2 when connected to the circuit described in connection with Fig.1* i; the same as those of the device illustrated in While I have shownand described and have pointed out in the annexed claims certain novelfeatures of the invention, it will be understood that various omissions,substitutions and changes in the forms and details of the deviceillustrated and in its use and operation may be made by those skilled inthe art without departing from the broad spirit and scope of theinvention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In combination, an electric discharge device comprising a container,electrodes sealed therein, a gaseous atmosphere therein, at least two ofsaid electrodes being main discharge supporting electrodes connected tothe terminals of an alternating-current source, two other of saidelectrodes extending along the discharge path between said mainelectrodes each being adjacent one of said main electrodes, each of saidauxiliary electrodes being connected through an impedance to a terminalof a current source of higher potential than that to which said maindischarge supporting electrodes are connected.

being connected through an impedance to a terminal of acurrent source ofhigher potential than that to which said maindischarge supportingelectrodes are connected, the main discharge supporting electrodes andthe auxiliary electrodes adjacenteach other having opposite polarity.

13. In combination, an electric discharge device comprising a container,electrodes sealed therein, a gaseous atmosphere therein, at least two ofsaid electrodes being main discharge supporting electrodes connected tothe terminals of an alternating-current source, two other of saidelectrodes extending along the discharge path between said mainelectrodes each being adja- "cent one of said main electrodes, each oi.said auxiliary electrodes being connected through an impedance to aterminal of a current source of higher potential than that to which saidmain discharge supporting electrodes are connected, the main dischargesupportingelectrods and the auxiliary electrodes adjacent each otherhaving opposite polarity, the parts of said auxiliary electrodesadjacentsaid main electrodes being covered with an insulation material.

4. In combination, an electric discharge device comprising a container,electrodes sealed therein, a gaseous atmosphere therein, at least two ofsaid electrodes being main discharge supporting electrodes connected tothe terminals of an alternating-current source, two other of saidelectrodes extending along the discharge'path between said mainelectrodes each being adjacent one of said main electrodes,'each of saidauxiliary electrodes being connected through an impedance to a terminalof a current source of higher potential than that to which said maindischarge supporting electrodes are connected, the main dischargesupporting electrodes and the auxiliary electrodes adjacent each otherhaving opposite polarity, the adjacent parts ofsaid auxiliary electrodesbeing surrounded by a grid supported by the inner wall of saidcontainer.

RIK LEMs.

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